1. Field of the Invention
The present invention relates to a pattern forming method and a manufacturing method of a semiconductor device which are used for processing of a substrate such as a semiconductor substrate, a glass substrate or a resin substrate, and more particularly to a pattern forming method and a manufacturing method of a semiconductor device which utilize a two-layer resist process.
2. Description of the Background Art
In recent years, with high integration of semiconductor devices, a wiring line and a separation width required in a manufacturing process are further miniaturized. Generally, this type of miniaturized pattern is formed by forming a resist pattern by a photolithography technology and etching an underlying film with the formed resist pattern being used as a mask. Therefore, the photolithography technology is important in formation of a fine pattern. However, there arises a limit in miniaturization of the photolithography technology since miniaturization is restricted by an exposure wavelength.
Thus, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2003-303757 proposes a method of using a water-soluble resin coating forming agent to narrow a hole diameter of a hole resist pattern formed by photolithography processing. In this method, resist patterns are formed on a substrate by photolithography processing, and then the resist patterns are coated with the water-soluble resin coating forming agent. Subsequently, a heat treatment is performed to thermally contract the coating forming agent, and this thermal contraction function is utilized to narrow a gap between the resist patterns. Then, after the coating forming agent is removed by a pure water rinse, the substrate is selectively etched with the resist pattern having the narrowed hole diameter being used as a mask.
According to this method, the hole diameter can be reduced to be smaller than a dimension restricted in photolithography. However, a process of removing the coating forming agent is newly required, and the number of processes is increased as compared with a conventional resist pattern forming method. Further, after removal of the coating forming agent, residual dross is apt to be generated, and this residual dross may possibly adversely affect subsequent formation of the pattern.
As a method of reducing an opening dimension of a resist pattern, the method of utilizing thermal contraction of a coating forming agent has been conventionally proposed in this manner, but this method may result in a problem of an increase in the number of processes such as rinse processing of the coating forming agent.